Casein glue



.. Patented a. 26, 192

UNITED STATES PATENT- OFFICE.

HENRY L. PRES'IHOLDT, 0F MINNEAPOLIS, MINNESOTA.

GASEIN GLUE,

No Drawing.

My present invention provides a new composition of matter, herein designated as casein glue, but which, from its broader aspect, is an adhesive composition adapted to be used, by itself or commingled with other substances, as an adhesive coating.

This composition involves, as its most important elements, casein, lime and a salt of formic acid, preferably sodium formate. This composition is greatly improved by the addition of other substances, such as sodium fluoride, sodium sulphite, magnesium oxide, zinc oxide and an oil, referably kerosene. The lime used is advisa ly calcium hydroxide or slacked lime.

I have obtained a very highly elficient glue or adhesive by the use of the above noted substances in accordance with the following formula:

Parts. Gasein to'75 Calcium hydroxide 10 to 22 Sodium fluoride 2 to 10 Sodium sulphite 3 to 8 Magnesium oxide; 5 to 14 .Zinc oxide 1 to f Sodium formate to 3 Kerosene 3 to 5 Zinc oxide delays or retards the formation of ammonia, which tends to form in the glue emulsion, and prevents staining, so that no stains will be produced by the reaction of the Application filed April 17, 1922. Serial No. 554,205.

and when it is to be used, it will be intro-- duced into water to' form an emulsion, and

it is then, of course, the chemical reactions that develop the adhesive qualities of the composition, will take place. After these reactions have taken place, the emulsion is adapted to be used as 9. Inc or as a coating or to be commingled with such as paint or calcimine, which contain certain color pigments. When desired, however, the color pigments may be commingled with the dry composition. When the composition is to be used simply as a glue, no additions to the formula given, except Water, will be re uired.

Casein, aving colloidal properties, when treated with the chemicals used in this formula, produces adhesive qualities very valuable for gluing of wood. I use calcium h droxide, which is a slack lime but must he what is commonly known as a high grade calcium lime. Sodium sulphite and sodium fluoride are utilized as a solvent, but either 7' of these will not dissolve casein unless calcium hydroxide, in-the' proportion stated, is used. This mixture, however, has a tendency of becoming very liquid and losingits waterproof qualities, and for that reason, a re small addition of magnesium oxide is introduced, which imparts to the glue emulsion the necessary waterproof qualities. Zinc oxide is introduced for the purpose of adding additional body to the glue and also to so impart a white color, so that in the event of the glue penetratin the pores of the wood, the glue will not s ow to the disadvantage when the wood is finished. Zinc oxide has another peculiar property of retarding the es formation of ammonia. This glue emulsion, by uniting with the gallic and tannic acid in the wood, forms a stain unless the zinc oxide is introduced. T use sodium formats as a re-agent for the purpose of preventing co the decomposition and formation of nitrogen. Zinc oxide adds to the body of the glue and has a bleaching action, but may be omitted where a bleached glue or a glue that other substances, 6 i

would produce stain is not required. Kerosens is desirable es ecially because it keeps down the dust in t e srocess of manufacture, but may be omitte What I claim is: 1. An adhesive composition made substantially in accordance with the following formula:

Part5.

Casein 50 to 75 Calcium hydroxide 10 to 22 Sodium fluoride 2 to 10 Sodium sulphite 3 to 8 Magnesium oxide 5 to 14.-

Sodium formate", to 3 2. An adhesive composition made in accordance with the following formula:

v Pnrtm. Casein 50 to 75 Calcium hydroxide 10 to 22 Sodium fluoride 2 to 10 Sodium sulphite 3 to 8 Magnesium oxide 5 to 1% Zinc-oxide 1 to Sodium formate A to 3 Kerosene 3 to 5 In testimony whereof I affix my signature.

HENRY L. PRESTHOLDT. 

